Noonday Dolomite Research Articles

Hydrogeology of desert springs in the Panamint Range, California, USA: Geologic controls on the geochemical kinetics, flowpaths, and mean residence times of springs

AbstractOver 180 springs emerge in the Panamint Range near Death Valley National Park, CA, yet, these springs have received very little hydrogeological attention despite their cultural, historical, and ecological importance. Here, we address the following questions: (1) which rock units support groundwater flow to springs in the Panamint Range, (2) what are the geochemical kinetics of these aquifers, and (3) and what are the residence times of these springs? All springs are at least partly supported by recharge in and flow through dolomitic units, namely, the Noonday Dolomite, Kingston Peak Formation, and Johnnie Formation. Thus, the geochemical composition of springs can largely be explained by dedolomitization: the dissolution of dolomite and gypsum with concurrent precipitation of calcite. However, interactions with hydrothermal deposits have likely influenced the geochemical composition of Thorndike Spring, Uppermost Spring, Hanaupah Canyon springs, and Trail Canyon springs. Faults are important controls on spring emergence. Seventeen of twenty‐one sampled springs emerge at faults (13 emerge at low‐angle detachment faults). On the eastern side of the Panamint Range, springs emerge where low‐angle faults intersect nearly vertical Late Proterozoic, Cambrian, and Ordovician sedimentary units. These geologic units are not present on the western side of the Panamint Range. Instead, springs on the west side emerge where low‐angle faults intersect Cenozoic breccias and fanglomerates. Mean residence times of springs range from 33 (±30) to 1,829 (±613) years. A total of 11 springs have relatively short mean residence times less than 500 years, whereas seven springs have mean residence times greater than 1,000 years. We infer that the Panamint Range springs are extremely vulnerable to climate change due to their dependence on local recharge, disconnection from regional groundwater flow (Death Valley Regional Flow System ‐ DVRFS), and relatively short mean residence times as compared with springs that are supported by the DVRFS (e.g., springs in Ash Meadows National Wildlife Refuge). In fact, four springs were not flowing during this campaign, yet they were flowing in the 1990s and 2000s.

A slippery slope for Cryogenian diamictites?

AbstractThe Death Valley region has previously been claimed to preserve the sedimentary records of both the Sturtian and Marinoan snowball Earth events within the Kingston Peak Formation, which outcrops in a number of disconnected mountain ranges. In this context, new sedimentary logs are presented together with detailed clast textural analyses which allow diamictites of the Alexander Hills and the Saddle Peak Hills to be compared in detail for the first time, and to be contrasted with rocks of well‐established glaciogenic origin from the Kingston Range. Notably, in the Saddle Peak Hills, clasts identical in composition and facies to that of the Noonday Dolomite—a unit previously interpreted as the post‐Marinoan cap carbonate—are incorporated into diamictites at the top of the Kingston Peak Formation. Combined with the carbonate‐rich composition of rocks at the top of the formation, these observations suggest that the uppermost diamictites of the Saddle Peak Hills and Alexander Hills are genetically related to the Noonday Dolomite and are unrelated to glacial processes. We propose that they formed through local slope foundering and basinward collapse of the adjacent carbonate platform, substantiating recent interpretations of Noonday carbonate platform dynamics, and demonstrating that they are genetically unrelated to Cryogenian glaciation. Thus, clast textural analyses play a valuable role in establishing whether contested ‘snowball Earth’ outcrops are truly glaciogenic or simply the product of local slope collapse.

Detrital zircon provenance and paleogeography of the Pahrump Group and overlying strata, Death Valley, California

The Mesoproterozoic and Neoproterozoic Pahrump Group of Death Valley, California spans ca. 1300–635Ma and provides a >500 million-year record of geologic events in southwestern Laurentia. The strata analyzed include preserved sequences separated by unconformities recording syn-Rodinia basin development (Crystal Spring Formation); Rodinia stability; regional extension culminating in Neoproterozoic rifting of the Laurentian margin of Rodinia (Horse Thief Springs through Johnnie Formations); and multiple phases of glacial sedimentation and subsequent cap carbonate deposition (Kingston Peak Formation and Noonday Dolomite). U-Pb detrital zircon analyses were conducted on samples from the entire Pahrump Group and the Noonday Dolomite in the southeastern Death Valley region (20 samples, 1945 grains) to further constrain hypotheses for regional basin development during the development of the southwestern Laurentian margin.Our interpretation of provenance data expands upon and clarifies previous models defining a series of tectonostratigraphic units including: (A) the <1400Ma basal conglomerate of the Crystal Spring Formation, comprised of metasedimentary quartzite clasts, and exhibiting a unimodal detrital zircon sample distribution at 1690Ma with northerly source; (B) the ca. 1320–1080Ma Crystal Spring Formation exhibiting unimodal zircon distributions derived from southerly, local Paleoproterozoic basement sources punctuated by a ca. 300Ma duration unconformity; (C) the ca. 780–740Ma sequence of the Horse Thief Springs Formation, Beck Spring Dolomite, and KP1 unit of Kingston Peak Formation deposited in a marine basin with mixed southwestern Laurentian provenance; (D) a ca. 710–635Ma glaciogenic sequence (KP2-KP4 members of Kingston Peak Formation), recording the onset of Rodinia rifting, and Sturtian and Marinoan “Snowball Earth” intervals with provenance data suggesting derivation from erosion and recycling of older Pahrump Group strata; (E) the ca. 635Ma cap dolostone of the Sentinel Peak Member of the Noonday Dolomite, representing post-glacial drainage reorganization with more regional provenance; followed by (F) the <635Ma strata of the Radcliff Member of the Noonday Dolomite, showing a marked shift to bimodal age distributions, indicating derivation from local basement sources. These data synthesize and complement previous provenance studies from overlying units and result in the addition of ca. 500Ma of new provenance analysis for the southwestern Laurentian margin.

Chapter 40 The Kingston Peak Formation in the eastern Death Valley region

Abstract The late Neoproterozoic Kingston Peak Formation (Fm.) is a several-kilometre-thick sedimentary succession primarily influenced by syndepositional tectonism and located in the region around Death Valley, California (Fig. 40.1). Its distribution is divisible into an eastern facies assemblage, the subject of this paper, and a western facies assemblage covered in a separate chapter. The diamictite-bearing Kingston Peak Fm. is bounded by the underlying shallow platform carbonates of the Beck Spring Fm. and overlain by the Noonday Dolomite. There is an absence of direct palaeolatitude or radiometric age constraints and any correlation is based on broad similarities with other coarse-grained strata (diamictite) located in a northward trending belt along the Cordilleran miogeocline. The overlying Noonday Dolomite has been interpreted to be a late Cryogenian ‘cap carbonate’ and shares a set of unique facies associations and isotopic and lithological characteristics with other late Neoproterozoic post-glacial carbonate intervals in Namibia, Canada, Australia and Brazil. Research to date has focused on understanding local basin evolution, glacial sedimentology, correlation between the eastern and western facies assemblages and initiation and development of the North American Cordillera. The intimate association of tectonic and glacial facies with rapid local thickness and facies changes corresponding with syn-sedimentary faulting is the most distinctive stratigraphic characteristic of the Kingston Peak Fm. The complex local stratigraphy complicates correlation both within the Death Valley region as well as globally, and pending absolute age dates, does not fit easily with conventional Cryogenian Period glacial models identifying two or more discrete ice ages.

Chapter 41 Glaciogenic and related strata of the Neoproterozoic Kingston Peak Formation in the Panamint Range, Death Valley region, California

Abstract Glaciogenic deposits in the Death Valley region occur within the Neoproterozoic Kingston Peak Formation (Fm.). In the Panamint Range, immediately west of Death Valley, the formation is as much as 1000 m thick and is continuously exposed for nearly 100 km along the strike of the range. Although the strata are variably metamorphosed and locally exhibit pronounced ductile strain, original sedimentary textures are well preserved in many places. Diamictite occurs in two distinct intervals, a lower one comprising the Limekiln Spring and Surprise members, and an upper one, the Wildrose Sub-member of the South Park Member. Lonestones, bullet-shaped and striated clasts, and rare dropstones within these members, along with the impressive lateral continuity of diamictic units, support a glacial origin. Both diamictic intervals are succeeded by well-defined carbonates, the oldest is the Sourdough Member of the Kingston Peak Fm. and the younger one is the Sentinel Peak Member of the overlying Noonday Dolomite. The stratigraphic succession between the Sourdough Member and the Wildrose Sub-member (i.e. the Middle Park, Mountain Girl and Thorndike sub-members of the South Park Member) is c. 300 m thick and includes lithologies recording deposition in braided fluvial to platform carbonate settings. Lithostratigraphic and chemostratigraphic profiles of δ 13 C for the Sourdough (–3‰ to +2‰, increasing upward) and Sentinel Peak (–3‰ ±1‰) members suggest correlation with, respectively, the older Cryogenian (commonly referred to as ‘Sturtian’ in previous literature) and younger Cryogenian (commonly referred to as ‘Marinoan’ in previous literature) cap-carbonate sequences recognized worldwide. Potentially economic uranium deposits (secondary brannerite) occur in graphitic schist of the Limekiln Spring Member and sub-economic uranium and thorium (hosted by detrital monazite) occur within quartz-pebble conglomerate in the South Park Member. The Kingston Peak Fm. strata in the Panamint Range contain no fossils, radiometric age control or primary magnetizations.

Base- and precious-metal deposits in the Basin and Range of Southern California and Southern Nevada—Metallogenic implications of lead isotope studies

Southern California and southern Nevada contain abundant lead–zinc deposits with strikingly different characteristics. On the west, the Darwin Terrane contains abundant Jurassic and Cretaceous intrusions surrounded by lead–zinc skarn and replacement deposits rich in pyrite and manganese minerals. The Tecopa Terrane is east of the Darwin Terrane and contains some lead deposits that are hosted by the Proterozoic Noonday Dolomite. These lead deposits have no consistent relation to igneous rocks; they contain mainly galena, and are devoid of pyrite and manganese minerals. Other skarn and vein deposits in the Ivanpah and Tecopa districts are more closely associated with igneous rocks. Mississippi Valley type lead–zinc deposits are present still farther to the east in the Goodsprings Terrane in Nevada. These deposits are hosted by breccias formed below the Mississippian–Pennsylvanian unconformity and are unrelated to igneous rocks. Deposits in the Darwin Terrane have lead isotopic signatures that lie along a mantle–sediment mixing line indicating that they formed in a continental arc setting analogous to that for the plutons in the Sierra Nevada batholith [Chen, J.H. and Tilton, G.R., 1991. Application of lead and strontium isotopic relationships to the petrogenesis of granitoid rocks, central Sierra Nevada batholith, California. Geological Society of America Bulletin 103, 439–447]. Encroachment of this continental arc on the North American continent in the eastern part of the Darwin Terrane resulted in a lead isotopic signature that is like that of the strongly contaminated plutons [Chen, J.H. and Tilton, G.R., 1991. Application of lead and strontium isotopic relationships to the petrogenesis of granitoid rocks, central Sierra Nevada batholith, California. Geological Society of America Bulletin 103, 439–447]. Many deposits from the Inyo Mountains on east side of the Owens Valley have lead isotopic signatures that reflect this encroachment. To the east in the Tecopa Terrane, encroachment of the continental arc on the Mojave crust resulted in partial melting of 1.7 Ga amphibolite and granulite facies rocks to produce the plutons and mineral deposits associated with plutons in this terrane. Lead from deposits in this terrane hosted in the Proterozoic Noonday Dolomite and associated rocks have a lead isotope signature that reflects hydrothermal circulation of fluids in the Mojave supracrustal rocks. The boundary between the Darwin Terrane and the Tecopa Terrane lies just west of the Ash Valley–Panamint Range Fault and is bounded by the Towne Fault on the north and the Garlock Fault on the south. Lead isotopic data from the Goodsprings district in southwestern Nevada, east of the Tecopa Terrane, form a 1.45 Ga linear array that is indicative of Mississippi Valley type mineralization. Although we have no independent evidence of the timing of the tectonic events that formed these deposits, it is likely that all formed as a result of the Mesozoic collision of the Panthalassen crust with the North American continent.

The relationship between the Neoproterozoic Noonday Dolomite and the Ibex Formation: New observations and their bearing on ‘snowball Earth’

The Neoproterozoic Ibex Formation (Death Valley region, California) is commonly interpreted as a coeval basinal facies to the Noonday Dolomite carbonate platform. However, in some areas (e.g., the Black Mountains, Death Valley), the Ibex Formation is found to rest on the eroded surface of the lower Noonday Dolomite and older units. Sediment-filled grikes root from the top of the eroded lower Noonday Dolomite, followed by the subsequent deposition of the Ibex Formation. Thus, the lower Noonday Dolomite is not considered coeval with all of the Ibex Formation as they are separated by a significant unconformity. At the type section in the Ibex Hills, the basal Ibex Formation commonly consists of polymict conglomerate and laminated mudstone; the upper surface of the mudstone is pierced by large angular clasts of underlying units, including distinctive lower Noonday Dolomite tubestone lithotypes. Here, a finely-laminated pink dolostone that records negative δ 13C values caps the basal Ibex conglomerate. Several interpretations of the new observations are possible. The erosional unconformity upon which the Ibex is deposited may be glacio-eustatic in origin, the basal conglomerate would represent glaciogenic ice rafted debris, and the overlying dolostone is a classic cap carbonate (noted atop many Neoproterozoic glacial deposits worldwide). Combined with the record from underlying units, the Death Valley succession would then unambiguously record three discrete Neoproterozoic ice ages with cap carbonates in a single succession. Alternatively, the sequence boundary could represent local tectonic activity rather than glacioeustacy.

Origin and Significance of Tube Structures in Neoproterozoic Post-glacial Cap Carbonates: Example from Noonday Dolomite, Death Valley, United States

Abstract The Neoproterozoic Noonday Dolomite (Death Valley, USA), a post-glacial cap carbonate, contains closely packed, meter-long, cm-wide, tube-like structures that define the vertical accretion direction. Similar tubestones are known from post-glacial cap carbonates in Namibia and Brazil. In vertical cross section, the tubes average 2 cm in diameter, pinch and swell greatly along their length, may bifurcate and coalesce, and are filled with brown laminated micrite/microspar where best preserved. The tubes do not root or terminate in a particular layer and are randomly distributed where present. The laminated host rock is composed of an early lithified, microclotted fabric with framework void space filled with sparry dolomite cement. The contact between the tube fill and the host rock is diffuse and feathered; commonly, wisps of laminated host rock cross the tube fill and bridge between adjacent stromatolitic structures, compartmentalizing the tubes. The tubes likely result from the contemporaneous int...

Neoproterozoic Carbonate Shrubs: Interplay of Microbial Activity and Unusual Environmental Conditions in Post-Snowball Earth Oceans

Other| October 01, 2003 Neoproterozoic Carbonate Shrubs: Interplay of Microbial Activity and Unusual Environmental Conditions in Post-Snowball Earth Oceans MARGARET L. FRAISER; MARGARET L. FRAISER 1Department of Earth Sciences, University of Southern California, Los Angeles, CA 90089, fraiser@usc.edu Search for other works by this author on: GSW Google Scholar FRANK A. CORSETTI FRANK A. CORSETTI 1Department of Earth Sciences, University of Southern California, Los Angeles, CA 90089, fraiser@usc.edu Search for other works by this author on: GSW Google Scholar Author and Article Information MARGARET L. FRAISER 1Department of Earth Sciences, University of Southern California, Los Angeles, CA 90089, fraiser@usc.edu FRANK A. CORSETTI 1Department of Earth Sciences, University of Southern California, Los Angeles, CA 90089, fraiser@usc.edu Publisher: SEPM Society for Sedimentary Geology Accepted: 15 Jun 2003 First Online: 03 Mar 2017 Online ISSN: 1938-5323 Print ISSN: 0883-1351 Society for Sedimentary Geology PALAIOS (2003) 18 (4-5): 378–387. https://doi.org/10.1669/0883-1351(2003)018<0378:NCSIOM>2.0.CO;2 Article history Accepted: 15 Jun 2003 First Online: 03 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation MARGARET L. FRAISER, FRANK A. CORSETTI; Neoproterozoic Carbonate Shrubs: Interplay of Microbial Activity and Unusual Environmental Conditions in Post-Snowball Earth Oceans. PALAIOS 2003;; 18 (4-5): 378–387. doi: https://doi.org/10.1669/0883-1351(2003)018<0378:NCSIOM>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyPALAIOS Search Advanced Search Abstract A previously undescribed carbonate-shrub facies has been discovered in the lower member of the Noonday Dolomite—a Neoproterozoic post-glacial cap carbonate. This unusual facies consists of centimeter-scale structures composed of micrite and encased in early-marine cement, and exhibits an overall clotted, mottled appearance. Shrub architecture is characterized by occurrence of a central stalk with diverging branches that are composed of micrite leaves. A combination of biological, environmental, and diagenetic influences contributed to the growth and present appearance of Noonday Dolomite carbonate shrubs. Comparison with modern and ancient known abiogenic and biogenic shrub-like structures indicates that microbial communities were most likely responsible for at least localizing and initiating calcium carbonate growth in the Noonday Dolomite shrubs, although no undisputable microbial fossils have yet been discovered. Diagenetic processes may have obliterated Noonday Dolomite shrub microstructure and obscured any former fossil evidence. Unusual seawater conditions (high alkalinity/extreme calcium carbonate supersaturation) were vital for shrub growth. This research highlights a possible biologic component in Neoproterozoic post-glacial cap carbonates where most studies have focused on abiogenic processes. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Stratigraphic investigations of carbon isotope anomalies and Neoproterozoic ice ages in Death Valley, California

An unusual richness of biogeochemical events is recorded in Neoproterozoic‐ Cambrian strata of the Death Valley region, California, United States. Eight negative carbon isotope (d13C) excursions are found in carbonate units between 1.08 Ga and the Precambrian/Cambrian boundary; four of these excursions occur in carbonates that contain textural features similar to those found globally in postglacial ‘‘cap carbonates’’ (including one or more of the following: laminite with rollup structures, apparent ‘‘tube rocks,’’ seafloor precipitates, and sheet-crack cements). However, only two of these units, the Sourdough limestone member of the Kingston Peak Formation and the Noonday Dolomite, rest directly upon glacial strata. The basal Beck Spring Dolomite and the Rainstorm Member of the Johnnie Formation each contain negative excursions and cap-carbonate‐like lithofacies, but do not rest on known glacial deposits. If the negative d13C excursions are assumed to record depositional processes, two equally interesting hypotheses are possible: (1) The Death Valley succession records four glacial pulses in Neoproterozoic time, but glacial units are not preserved at two stratigraphic levels. (2) Alternatively, other global oceanographic processes can cause negative excursions and cap-carbonate‐ like facies in addition to, or independent of, glaciation.

Two diamictites, two cap carbonates, two δ13C excursions, two rifts: The Neoproterozoic Kingston Peak Formation, Death Valley, California: Comment and Reply

The prima facie evidence for the age of the Proterozoic Kingston Peak Formation cited by [Prave (1999)][1] is the δ13C value of carbonate in metalimestones in the middle and upper parts of the formation. Those data and the C-isotope composition of the overlying Noonday Dolomite were used by [Prave

Two diamictites, two cap carbonates, two δ13C excursions, two rifts: The Neoproterozoic Kingston Peak Formation, Death Valley, California

Research Article| April 01, 1999 Two diamictites, two cap carbonates, two δ13C excursions, two rifts: The Neoproterozoic Kingston Peak Formation, Death Valley, California A. R. Prave A. R. Prave 1Crustal Geodynamics Group, School of Geography and Geosciences, University of St Andrews, St Andrews, Fife KY16 9ST, UK Search for other works by this author on: GSW Google Scholar Geology (1999) 27 (4): 339–342. https://doi.org/10.1130/0091-7613(1999)027<0339:TDTCCT>2.3.CO;2 Article history first online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation A. R. Prave; Two diamictites, two cap carbonates, two δ13C excursions, two rifts: The Neoproterozoic Kingston Peak Formation, Death Valley, California. Geology 1999;; 27 (4): 339–342. doi: https://doi.org/10.1130/0091-7613(1999)027<0339:TDTCCT>2.3.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract Stratigraphic mapping of the Neoproterozoic glaciogenic Kingston Peak Formation (Death Valley, California) provides evidence for two temporally discrete extensional deformation episodes. These episodes are bracketed by the Sourdough Limestone and Noonday Dolomite, the facies characteristics and δ13C data (ranging between 2.15 and −2.56‰ and −1.88 and −4.86‰, respectively) of which make them equivalent to Sturtian and Varangian age cap carbonates, respectively. This constrains the two extensional episodes along the southwestern margin of Laurentia to ca. 700 Ma and ca. 600 Ma. These observations and data show that the field evidence for mid-Neoproterozoic breakup and the predictions from tectonic subsidence curves for a latest Neoproterozoic breakup are both correct. Thus, Neoproterozoic plate reconstructions must account for two discrete rift episodes separated by 100 m.y. or more. Confining rifting to within the Kingston Peak Formation thereby places the younger Proterozoic rocks of the southwestern Great Basin in the rift to drift tectonic phase. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Tectonic subsidence of the early Paleozoic passive continental margin in eastern California and southern Nevada

Quantitative analysis of tectonic subsidence in Cambrian and Ordovician platform carbonates and associated strata exposed in the Spring Mountains (Nevada) and the Nopah, Funeral, and Inyo Ranges (California) indicates that subsidence associated with this segment of the early Paleozoic passive continental margin is exponential in form, consistent with thermal contraction of the lithosphere following extension. As in other parts of the North American Cordillera, continental separation in the southern Great Basin appears to have taken place between 590 and 545 Ma. These results are not sensitive to uncertainties in stratigraphic thickness, biostratigraphic age control, or paleobathymetry. Uncertainties in the Cambrian time scale lead to predictable variations in the inferred time of onset of thermal subsidence, but they have no effect on the inferred stratigraphic position of the rift to post-rift transition. A younger age for the base of the Middle Cambrian results in a younger inferred age of onset of thermal subsidence accompanied by greater rates of subsidence during the Cambrian, whereas a significantly older estimate of the onset of thermal subsidence can be obtained only if the base of the Middle Cambrian is substantially older than 540 Ma, a possibility that is inconsistent with available data. Results of the subsidence analysis are particularly significant because this is one of the few regions along the length of the North American Cordillera where they can be compared directly to the geologic evidence for syn-rift and post-rift deposition. Basement-involved faulting associated with the Amargosa basin (aulacogen) ceased during deposition of the Noonday Dolomite, which is thought to be older than 700-680 Ma on the basis of stromatolites of late Riphean affinity. The overlying Johnnie Formation contains supposed Vendian stromatolites (younger than 700-680 Ma). If it is assumed that our results indicate the timing of the final rift to post-rift transition, then either the ages inferred from stromatolites are incorrect or the lithosphere was thinned regionally after deposition of the Noonday. The latter possibility is supported by limited geologic evidence for extension in latest Proterozoic and Early Cambrian time. The lack of appreciable physical evidence for crustal extension after deposition of the Noonday, however, may imply that (1) a uniform extension model for lithospheric thinning is inappropriate for this part of the margin or that (2) some or all of the localities studied are continentward of the hinge zone, and that the observed subsidence is exaggerated by flexural loading in a deeper basin to the west.

Paleotectonic and Stratigraphic Implications of the Kingston Peak-Noonday Contact in the Panamint Range, Eastern California

Geologic mapping in parts of the southern Panamint Range, eastern California, has documented critical stratigraphic relationships at the upper Proterozoic contact between the Kingston Peak Formation and Noonday Dolomite. These relations bear significantly upon the timing and style of development of the latest Proterozoic and Paleozoic continental margin of western North America. They include: (1) an unconformity below Wildrose diamictite, interpreted as glaciogenic, the uppermost Kingston Peak unit; (2) diamictite similar to Wildrose diamictite interbedded within carbonate strata of the overlying basal Noonday Dolomite; and (3) interfingering between rocks of the Kingston Peak and Noonday formations. The Kingston Peak-Noonday contact is thus complex and variable in character and does not represent a regional unconformity. Instead, it marks a transition from rift to post-rift sedimentation without any hiatus and shows there was no regional doming during rifting. The stratigraphic relations also demonstrate...

Algal and cryptalgal structures and platform environments of the late pre-Phanerozoic Noonday Dolomite, eastern California

A late pre-Phanerozoic platform, almost continuously blanketed by algal mats, is recorded in the distributional pattern, composition, and textures of the Noonday Dolomite, Death Valley region, California. The platform, apparently L-shaped, was at least 160 km long. It lay west and south of the Nopah upland, established much earlier, and north of a fault-bounded east-trending depression containing units of the older Pahrump Group. A lower member of the Noonday consists of very finely crystalline, laminated, and relatively pure dolomite. The laminations, although commonly deposited horizontally, also outline mounds having a synoptic relief of a few metres to nearly 200 m. Algal or cryptalgal fabrics are common. Especially large mounds in the Nopah Range lie on the down-dropped south side of a contemporaneous fault, indicating tectonic control of size and location. The laminated mounds are characterized by large-scale vertical stacking, best explained as produced by differential growth of algal mats. The configuration of the laminations indicate that the mats grew to depths of at least 100 m but probably did not extend more than 150 m below the mound crests. The absence in the lower member of features attributable to moving water and the paucity of clearly detrital material indicate quiet water and very low relief in the bordering land. An upper member consists of (1) discontinuous bodies of thinly and evenly bedded siltstone and silty dolomite that ordinarily occupy the deeper of the intermound lows; (2) a laterally continuous unit of silty dolomite with wavy laminations and small, rippled to subhemispherical, laterally linked stromatolites; and (3) an upper unit of massive to laminated silty dolomite, containing large domal and bosslike stromatolites and associated with bodies of strongly cross-bedded quartz-dolomite sandstone. These features evidence the entry onto the platform of detritus supplied by increasingly stronger uplift of the Nopah Upland and the sweeping of the platform by increasingly stronger currents. We interpret the carbonate of the lower member and much of the carbonate of the upper member as having been precipitated from ambient waters by removal of CO2 during algal photosynthesis.

Giant Stromatolites and Associated Vertical Tubes from the Upper Proterozoic Noonday Dolomite, Death Valley Region, Eastern California

Stromatolitic domes having apparent growth reliefs up to 100 m or more characterize the lower member of the Noonday Dolomite, late Proterozoic, Death Valley region, eastern California. Long to short, subparallel, initially subvertical tubes penetrate the bedding of these structures at angles that range from 90° where stratification was initially horizontal to downslope angles up to 110° (and acute upslope angles) as initial dips increase. Tubes generally are missing where initial dips exceed 20°. They are common in the larger buildups and most abundant in the upper and central parts of these. They may be open or filled with coarsely sparry secondary dolomite, medium-gray ultra microgranular dolomite, silty brown dolomite, or drusy quartz. They pinch and swell irregularly along their length from a mean diameter of 1.5 cm and are subcircular to irregular in horizontal cross section. Secondary crystalline growths similar to those in many tubes are common along lamination surfaces and as irregular vug fillings. Weathering along intersecting fracture sets locally produces a subvertical lineation in the same orientation as associated tubes. Possible origins considered for the tubes and found improbable are: (1) metazoan burrows, (2) interspaces of columnar stromatolites, (3) columnar stromatolites, (4) solution pipes, and (5) root casts. Instead the spaces now represented by filled vugs, sparry lamination surfaces, and tubes are interpreted as having, in general, a common origin caused by the upward movement of fluids through the stromatolite mounds.

Limitations on Right-Lateral, Strike-Slip Displacement, Death Valley and Furnace Creek Fault Zones, California

Sedimentary units of late Precambrian and Cambrian age in the southern Death Valley–Kingston Range region of eastern California contain several through going linear features with configurations that apparently place a several-mile limit on the total right-lateral displacement that may be assigned to the Death Valley–Furnace Creek fault system. Much greater magnitudes have been suggested previously. Precambrian paleogeologic contacts, recorded in the northeastward truncation of successively older units of the Pahrump Group by the unconformity at the base of the Noonday Dolomite, can be traced discontinuously as nearly straight features from the Kingston Range west-northwestward to the Panamint Range, about 75 miles. A belt of talc mineralization, which also trends west-northwestward, is marked by a crudely linear arrangement of deposits reflecting the distribution of a dolomitic facies of a carbonate unit in the lower part of the Pahrump Group. An “algal” dolomite unit, which forms the lower part of the Noonday Dolomite, thins to the southwest and terminates along a line that can be traced northwestward for about 25 miles along the east margin of Death Valley to Virgin Spring Wash and probably thence westward to the southern part of the Panamint Range. The plots of these linear features, all of which apparently cross either the Death Valley fault zone or Furnace Creek fault zone, or both, indicate that no more than 5 and 2 miles, respectively, of right-lateral, strike-slip movement has occurred on these zones. Indeed, the position and orientation of the lines require no lateral displacement at all for their explanation. Similar limitations on movement along Death Valley fault zone seem to be imposed by the presence, on the east side of Death Valley, of a wedge of shale and graywacke within the Noonday Dolomite. The wedge thins and becomes progressively finer-grained northeastward. It also contains a basal conglomerate with clasts of the “algal” dolomite and the Kingston Peak Formation. These features suggest a source area west of southern Death Valley. Right-lateral, strike-slip movement of 10 miles or more on the Death Valley fault zone, if restored, would anomalously juxtapose the clastic wedge with a terrane in the Panamint Range where the “algal” dolomite is preserved. The possibility that large-scale, right-lateral displacement in the region of central and southern Death Valley has been accomplished by crustal flexing, as advocated by some geologists, remains unsupported by the available structural data and is difficult to reconcile with the configurations of the geologic lines.

Strata of Late Precambrian-Cambrian Age, Death Valley Region, California-Nevada

The Noonday Dolomite, Johnnie Formation, Stirling Quartzite, Wood Canyon Formation, and Zabriskie Quartzite, which seem best assigned to the late Precambrian-Cambrian interval, are a conformable and predominantly detrital part of the stratigraphic record of the Death Valley region. They can be traced from type localities in the Spring Mountains and in the well-known section in the Nopah Range southwestward to the Salt Spring Hills and Silurian Hills in southern Death Valley and southeastward to the Kingston Range-Winters Pass area. Satisfactory correlation of these widespread formations is facilitated by (1) regional persistence of most of the members as originally recognized in the Nopah Range, (2) the distinctive lithologic character of the Noonday Dolomite, and (3) the presence of two marker units--an oolite and a volcanic ash(?)--high in the Johnnie Formation. Isopachous contouring of the stratigraphic interval from the top of the Zibriskie Quartzite to the base of the Noonday Dolomite appears to outline a late Precambrian-Cambrian marine trough. The major axis of this trough strikes north-northwest and is approximately coincident with the present Amargosa Valley and southern Death Valley. Along this axis, the combined thickness of these strata or their apparent equivalents decreases progressively from nearly 12,000 feet in the Funeral Mountains to only a few hundred feet in the Marble Mountains 160 miles toward the south. The isopachous lines drawn near the southeastward bend in the Garlock fault zone are nearly parallel with this major break, and the projected zero contour is about 10 miles southwest of it. This pattern strongly suggests that the structural element south and southwest of the Garlock fault, generally referred to as the Mojave block, existed as a topographic high in late Precambrian-Cambrian time.

Geology of Central Panamint Range: ABSTRACT

The area is west of Death Valley, between Stovepipe Wells and Wildrose Canyon, a distance of 25 miles. Archean gneiss, exposed in two small areas, one at Wildrose Station, one on south flank of Tucki Mountain, is overlain by a 2,000-foot series of meta-graywackers and meta-conglomerates best exposed in Wildrose Canyon (Surprise formation? Upper Algonkian), and widely exposed 3,000 or more feet of younger series of variably metamorphosed graywackle, shale, conglomerate, dolomite, and gypsum (Telescope group? Upper Algonkian). East-dipping Paleozoic strata make up the east flank of the range: Lower Cambrian, Noonday dolomite (200-1,000 feet), Johnnie formation (2,500), Sterling quartzite (1,500), Wood Canyon formation (2,900); Middle Cambrian, Cadiz formation (700), Bonanza King formation (1,250), Racetrack dolomite (1,950); Upper Cambrian, Nopah formation (1,700); Lower Ordovician, Pogonip formation (1,950); Middle Ordovician, Eureka quartzite (400); Upper Ordovician, Ely Springs dolomite (1,300); Silurian (?), Hidden Valley dolomite (?) (700); Devonian, Lost Burro formation (l,500). Post-Devonian strata are not yet mapped. Total thickness, Cambrian through Devonian (19,550), of which 13,650 are Cambrian. A 12-mile-long quartz monzonite intrusive of presumed Nevadan age near the ccenter of the range appears laccolithic. Structural features include the east-dipping monocline of Paleozoic sediments on the east flank of the range, two northwest-trending anticlines in Algonkian strata on the west and south flanks of Tucki Mountain, and widely prevalent flat to low angle faulting. End_of_Article - Last_Page 140------------